Novel single beam technique for measuring nonlinear optical absorption of materials by using an electrically focus-tunable lens

Abstract

ABSTRACT: We have measured the two-photon absorption coefficients for CdS and ZnSe by using a new single beam setup based on the well-known Z-scan technique. This novel technique, which we have named “f-scan”, uses an electrically focus-tunable lens instead of a mechanical translation stage, simplifying the experimental setup and reducing dramatically the cost of equipment while maintaining the experimental sensitivity. Also we found, experimentally, that the technique is more robust to sample surface roughness and multiple scattering because of the elimination of the mechanical motion of the sample. In this paper we present the theory as well as the experimental implementation of the technique. Experimental results for CdS and ZnSe are presented and two-photon absorption coefficients are compared to the well-established values for these semiconductors in the literature. The f-scan opens the door to an affordable nonlinear optical technique for basic research and applications.